STUDIES AND RESEARCHES REGARDING THE ACTION OF THE HETEROSIS PHENOMENON IN F₁ AND F₂ FOR THE TOMATO HYBRIDS OBTAINED AT V.R.D.S. BUZAU, ROMANIA

The tomato breeding started at V.R.D.S. Buzău since the establishment of the institution in 1957. In over 50 years of activity, here was accumulated a valuable germplasm collection for this species with over 200 lines in an advanced breeding stage. In order to correspond to actual requirements, in 1996 research works started in order to obtain high quality hybrids for this species. After 10 years of studies and researches concerning a great number of hybrid combinations made between 200 selected genitors, in 2006 there were obtained the first significant results. Four hybrids named: H₁Bz, H₂Bz, H₃Bz, H₄Bz – were obtained that manifested the heterosis phenomenon (reproductive and adaptable). These hybrids were tested in greenhouses, solarium and open field exhibiting superior results when compared to the genitors and the control hybrid cultivar. The hybrid that manifested in the most pronounced way the heterosis phenomenon for F₁ was H₂Bz which surpassed the most valuable genitor with 36 t/ha in greenhouse, 22 t/ha in solarium and 12 t/ha in open field. The lowest heterosis effect was shown by H₃Bz which surpassed the most valuable genitor with 17.8 t/ha in greenhouse, 12 t/ha in solarium and 2.4 t/ha in open field. Even if the results registered for H3Bz are lower than the other studied hybrids, this hybrid ranked first in what concerned the early crop. In F₂ H₃Bz showed a yield ~20% higher than the registered in F1 in all three culture systems. In addition the yield of this hybrid in F₂ was higher than that of the genitors and the other studied hybrids.